The present invention relates to a swash plate type compressor which includes a cylinder block having formed therethrough a plurality of cylinder bores, a rotary shaft rotatably supported by the cylinder block, a swash plate fixed on the rotary shaft for rotation therewith and a plurality of pistons reciprocally slidable received in the cylinder bores and each engaged with the swash plate, wherein the cylinder block has formed therein a chamber accommodating therein the swash plate.
FIG. 4 shows a prior art swash plate type compressor which is disclosed by Japanese Patent Application Publication 2003-247488 and designated by 80 in the drawing. The swash plate type compressor 80 includes a housing 81 formed by a pair of cylinder blocks 90, a rotary shaft 82 rotatably supported by the cylinder block 90, a swash plate 83 fixed on the rotary shaft 82 for rotation therewith and a plurality of pistons 84. The cylinder block 90 has formed therethrough a plurality of cylinder bores 85 receiving therein the respective pistons 84 and a crank chamber 86 (or a swash plate chamber) accommodating therein the swash plate 82. The pistons 84 are engaged with the swash plate 83 and reciprocally slidable in the respective cylinder bores 85.
The compressor 80 further includes a rear housing having formed therein a suction chamber 87. A suction passage 88 is formed axially in the rotary shaft 82 for introducing refrigerant gas in the suction chamber 87 into the cylinder bore 85. The rotary shaft 82 has also formed therein a plurality of oil passages 89 extending in radial direction of the rotary shaft 82 for supplying lubricating oil contained in refrigerant gas to the crank chamber 86. Lubricating oil contained in refrigerant gas in the suction passage 88 is supplied to the crank chamber 86 by the centrifugal force resulting from the rotation of the rotary shaft 82.
The cylinder block 90 has also formed therethrough a communication passage 91 for providing fluid communication between the crank chamber 86 and the suction chamber 87. While the swash plate type compressor 80 is operating at a high speed, lubricating oil in the crank chamber 86 returns with refrigerant gas through the communication passage 91 to the suction chamber 87 that is lower in pressure than the crank chamber 86, so that the lubricating oil is prevented from being accumulated excessively in the crank chamber 87.
However, the lubricating oil accumulated in the crank chamber 86, stirred by the swash plate 83 and the piston 84 and splashed during the operation of the swash plate type compressor 80 offers resistance against the rotation of the swash plate 83. To prevent the lubricating oil from being stirred by the swash plate 83 in the crank chamber 86, it may be so arranged that the lubricating oil level in the crank chamber 86 is lowered so as to be located below the space where the swash plate 83 rotates and the piston 84 reciprocates. In order to lower the oil level without increasing the overall size of the swash plate type compressor 80, however, the diameter of the crank chamber 80 need be increased so as to increase the inner volume thereof because the size of the compressor 80 is restricted. In this case, the rigidity of the housing 81 may be reduced at positions around the bolts 92 fastening components (such as the cylinder blocks 90, etc.) that form the housing 81 of the swash plate type compressor 80, with the result that the housing 81 may be deformed and the fluid tightness thereof may be reduced, accordingly.
The present invention is directed to providing a swash plate type compressor which prevents lubricating oil in the crank chamber of the compressor from being stirred by the swash plate and ensures the fluid tightness of the housing, without increasing the size of the housing of the compressor.